MRWC Releases New Video on CSOs in the Merrimack River

The Merrimack River Watershed Council (MRWC) has released a new video and webpage explaining why sewage is frequently discharged into the Merrimack River, and what is being done to help solve the problem.

The 8-minute video, narrated by MRWC Environmental Science Fellow Jose Tapia, examines the causes of the Merrimack’s sewage discharges, known as combined sewer overflows (CSOs). The video also provides interviews with regional leaders who are trying to address the problem, as well as tips on what concerned residents can do to help. Watch the video below. 

Produced by Elevated Thought, a Lawrence-based art and social justice non-profit, this is the first video that specifically addresses CSOs in the Merrimack River. This video is paired with the release of a new educational webpage which further highlights important data points and describes the pathways to solving the problem.

CSOs have become a frequent news headline in the Merrimack Valley, and have fueled much discussion and debate on social media platforms. CSOs often occur during moderate to heavy rainstorms in five Merrimack Valley cities — Haverhill, Lawrence, Lowell, Nashua and Manchester — where street drains are connected to sewer lines. During rainstorms, too much water enters sewer lines and excess quantities are discharged into the river to prevent damage to sewer plants and sewage overflows into homes and businesses.

“CSOs are a relic of 19th and early 20th century sewer systems that were built in the Merrimack Valley’s industrial cities,” said John Macone, MRWC’s policy and outreach specialist. “Those old sewer systems were designed to dump all sewage into the river, and they are very expensive and complicated to replace.”

On average, about 500 million gallons of CSO wastewater is discharged into the Merrimack in a typical year. That’s a significant drop from 20 years ago, when an average of 780 million gallons were discharged in an average year.

The reduction is due to drought conditions in recent years, and also work being done in cities to replace their sewer lines and upgrade infrastructure. The cost of these upgrades can be in excess of $100 million, and progress can be slow because they are paid for almost entirely by sewer fees collected from city residents and businesses. However, lawmakers in Massachusetts are considering a plan which could provide up to $400 million for water and sewer projects. That funding will greatly increase the speed of CSO-related upgrades.

The year 2021 has already proven to be an unusually active year for CSOs. In the month of July — one of the rainiest Julys on record — over 160 million gallons of CSO waste have been discharged into the Merrimack, according to data from the region’s sewer treatment plants.